The present invention relates to a smart entry system for a vehicle.
A smart entry (R) system is known, in which a door unlock or an engine start of a vehicle is granted when verification of an ID (identification) code contained in an ID (identification) signal, which is transmitted by a portable device and received by an onboard device at the vehicle, is confirmed.
Specifically, in the above-described smart entry (R) system, as disclosed in US Patent Application Publication No. 2003/0014164 A1, when an operation of the door unlock is conducted by a passenger from outside the vehicle, the request signal is transmitted outside the vehicle by the onboard device. Herein, the ID signal containing ID code is transmitted in response to the request signal, and then the ID verification is conducted by the smart keyless (R) control unit of the onboard device that has received the ID signal. When the ID verification is confirmed, namely, when the ID code contained in the ID signal matches an ID code that is registered at the smart keyless (R) control unit, the control unit outputs a signal for granting the door unlock, so the door is unlocked.
In the above-described smart entry (R) system, likewise, the ID verification is also conducted when an operation of engine start is conducted by the passenger, and when the ID verifications is confirmed, the control unit outputs a signal for granting the engine start, so the engine is started.
Further, the above-described smart entry (R) system is configured to disable the ID code of the portable that has been mistakenly left in the vehicle when the door is locked, or to cancel this disablement of the ID code in case the above-described ID verification is confirmed when the door unlock operation is conducted from outside the vehicle.
More specifically, in the above-described smart entry (R) system, when the door lock operation is conducted, the request signal is transmitted inside the vehicle by the onboard device. Then, the portable device transmits the ID signal in response to the request signal, and then the ID verification is conducted by the smart keyless (R) control unit of the onboard device that has received the ID signal. When the ID verification is confirmed, it is considered that the portable device has been left behind mistakenly, and thus this situation is notified of with an alarm and the ID code of the portable device left behind is disabled. Thereby, the engine start with the operation of the portable device is prohibited. Also, in the above-described smart entry (R) system, when the door unlock operation is conducted after this disablement operation, the disablement of the ID code of the portable device is cancelled in case the above-described ID verification is confirmed. Thereby, the engine start is granted again when the ID code verification with the portable device is confirmed.
However, if the ID code is always disabled as described above when the ID verification is confirmed, any passenger who is present in the vehicle could not use the portable device, whose ID code has been disabled, to start the engine, so utility or facility of the smart entry (R) system would deteriorate.
Also, in the case where the portable device is left behind in the vehicle, even if the ID code of the portable device is disabled as described above, the portable device generally comprises a transponder and a key, and therefore there is a concern that an unauthorized person (thief) who gets in the vehicle could start the engine with the key of the portable device left behind and thereby the vehicle could be stolen.
Further, if the disablement of the ID code of the portable device is cancelled as described above, there is a similar concern that any unauthorized person (thief) could start the engine with the portable device whose ID code has become available and thereby the vehicle could be stolen.